Why a later Japanese victory at Guadalcanal had limited strategic payoff

What could Japan do after winning Guadalcanal later in the campaign?

It could buy time, perhaps a few months, but not stop the United States' larger mobilisation and advance.

The answer separates a local victory from the larger industrial and operational balance. Holding Guadalcanal would preserve a useful position for Japan and force the Allies to adjust their immediate plans. It would not stop the continuing American build-up or cure Japan's wider shortage of resources and replacement capacity. The estimated result is a delay of perhaps two or three months rather than a reversal of the Pacific War. A contested objective matters only if the victor has the strategic power to exploit it.